Abstract Parkinson disease (PD) is the second most common neurodegenerative disease. Solvents, pesticides and metals are suspected risk factors, but specific agents in these very broad categories remain to be identified conclusively. Epidemiologic and animal studies together indicate that two possible candidates are the industrial solvent trichloroethylene (TCE) and airborne manganese (Mn), a metal used as the active ingredient in some pesticides and released during fossil fuel combustion. However, there have been few human studies on the association between these exposures and PD. In addition, despite these exposures being common in the environment, studies of PD and TCE have focused on occupational exposures, while the few environmental studies of PD and airborne Mn have yielded conflicting results. The proposed K01 career award will provide the training and resources to use ?big data? and sophisticated geographic information system (GIS) techniques to conduct a large population-based case-control study of PD and environmental exposure to TCE and airborne Mn using previously collected nationwide data and GIS methods to examine these associations (Aims 1 and 2) and their potential interactions (Aim 3). This approach will allow us to quickly and cost-effectively conduct a well-powered, population-based study with geographically representative cases and controls. To complement this highly targeted approach focused on two common environmental exposures, we will apply established methods from cancer epidemiology to the same data to identify clusters of incident PD within the U.S. (Exploratory Aim 3). All aims will be completed using an existing large case-control study (89,790 incident PD cases and >22 million controls) of Medicare beneficiaries age >65 with detailed (9-digit zip code) residence data and demographic data. This work will build substantially on existing literature and promises to generate novel hypotheses on the environmental causes of an important disease known to have a strong environmental component and only symptomatic treatment.